1. Field of Invention
This invention relates to acoustic panels, and more particularly to panels usable in and around high speed gas flow areas of aircraft including the use as liners for jet and turbo-jet engines.
2. Description of the Prior Art
A preliminary search on the subject matter of this invention revealed Rutledge, U.S. Pat. No. 3,948,347; Cowan, U.S. Pat. No. 3,502,171; and Hankel, U.S. Pat. No. 3,977,492. These patents disclose sound absorbent materials having some of the elements found in the present invention, but neither patent suggests the combination of components presently disclosed and claimed which have been found to yield superior sound absorbing qualities, resistance to severe environment, provide a smooth near turbulance free high speed gas exposed surface and provides substantially no penetration of foreign matter into the acoustic material.
Other U.S. Patents of general interest which were found in the search are as follows:
U.S. Pat. No. 3,061,491; Sherrard, et al., Oct. 30, 1962 PA0 U.S. Pat. No. 3,166,149; Hulse, et al., Jan. 19, 1965 PA0 U.S. Pat. No. 3,211,253; Gonzalez, Oct. 12, 1965 PA0 U.S. Pat. No. 3,630,312; James R. Woodward PA0 U.S. Pat. No. 3,712,846; Daniels, et al., Jan. 23, 1973 PA0 U.S. Pat. No. 4,056,161; Allen, Nov. 1, 1977